Stringed instruments such as guitars sometimes have tremolo systems which a user may use to vary the tension in the strings. A tremolo system typically comprises a vibrato bar. The user may press the vibrato bar toward the instrument's body to lower the tension in the strings, and pull the vibrato bar away from the instrument's body to increase the tension in the strings thereby altering the pitch of sound produced by playing the strings.
U.S. Pat. No. 5,381,716 to May et al. discloses a tremolo system which includes a base plate and a block member. The base plate is attached to the upper surface of the instrument's body. The base plate has a pair of laterally opposed first bearing portions located within the body which cooperate with a pair of second bearing portions on the block member. The block member pivots about an axis below the upper surface of the body. The strings are attached to an upper portion of the block member above the pivot axis of the block member. Springs are attached between the body and a lower portion of the block member. A tremolo lever is attached to the upper portion of the block member. A user may vary the tension in the strings by raising or lowering the tremolo lever. When the lever is released the system returns to an equilibrium position under the influence of either the strings or the springs, depending on the direction of movement of the lever. The tension in the springs must be matched by the tension in the strings in order to ensure that the system returns to the equilibrium position.
The inventor has determined that there exists a need for improved tremolo systems which provide a user with the ability to vary the tension in the strings of a stringed instrument while playing the instrument.